JP2010515321A - Method and system for enhancing the security of electronic signature generation with a chip card - Google Patents

Abstract

  The present invention relates to a security enhancement method and system for generating an electronic signature using a chip card. The method and system of the present invention selects the essential data from the data, in particular to provide visual verification of the data to be signed and to ensure a reliable book title process. A method for increasing the security of a digital signature of data on a chip card includes the following steps. That is, a display (51) integrated with a chip card (5) is prepared, and a chip card for transmitting data to be signed from the chip card (5) to the terminal (2) and from the terminal to the chip card, respectively. A reader / writer (4) is prepared and the display (51) is visible to the user during data transmission between the terminal (2) and the chip card (5), and the chip card (5) and the terminal (2) are connected. Establish data transmission, start the signing process, transmit the data to be signed to the chip card (5) marked with essential data, select the marked data and display it on the chip card display (51) The selected state is displayed, the data to be signed is signed, and the signature is transmitted from the chip card (5) to the terminal (2).

Description

  The present invention relates to a method and system for increasing the security of electronic signature generation by a chip card. The method or system of the present invention provides, among other things, a visual confirmation of the data to be signed in order to ensure a reliable signature.

  A chip card, often referred to as a smart card or an integrated circuit card (ICC), is a dedicated plastic card with an embedded chip. A chip typically has hardware logic and memory and / or a microcomputer. There are different types of chip cards.

  The memory chip card simply serves to store data. They have only simple logic. On the other hand, processor chip cards usually have their own card operating system and often have cryptographic capabilities. Chip cards with cryptographic capabilities provide cryptographic algorithms in addition to the possibility of storing secret information such as cryptographic codes, so encryption or digital signature generation occurs inside the chip card, and the cryptographic code is read directly. Can not be.

  Since the secret or private code is stored on the chip card and does not leave it, it is almost impossible to find the code. Therefore, the generation of a signature by a chip card must be considered quite safe in principle. Electronic signatures offer several advantages for transactions over a network. For example, they guarantee the authenticity of the message. Most member states of the European Union have passed the law on electronic signatures in the meantime and are in compliance with the requirements of the EU directive 1999/93 / EC. In Germany and Europe, electronic signatures are generally legally equivalent to human signatures. Given the high level of security provided by chip cards in the generation of electronic signatures, chip cards are under the German Signature Law (SigG, German Electronic Signature Law) and Electronic Signature Ordinance (SigV, respectively) It is indispensable as a so-called signature generation device for generating an electronic version of a handwritten signature.

  Since chip cards have mostly no power supply and no keyboard or display, there is always a need for a card reader / writer as well as a terminal for displaying the interaction between data and the chip card. As a result, there must always be data communication between the terminal and the chip card to sign and display digital documents. Therefore, the data presented on the terminal display is really the data that the signer wants to sign with the chip card, that is, the user wants to sign what he sees (WYSIWYS-“What You See is What You Sign”) That is why signers must be able to rely on reliable transfer of data and reliable representation. However, the data communication between the terminal and the chip card as well as presenting the data to be signed on the terminal display is often referred to as a terminal problem and carries the potential risks that will be briefly described next.

  Often, personal computers (PCs) serve as terminals and computer screens serve as terminal displays. With this type of terminal, the user or signer cannot verify that the data displayed on the computer screen is the data that he or she really wants to sign. For example, malicious software (malware; eg “Trojans”) may be present on the PC. Malware changes or replaces the data on the PC so that the user sees the data he has signed on the computer screen, but eventually signs the data not displayed on the computer screen. The following example will further illustrate this point.

  Suppose a user wants to enter a bank transfer on his / her own personal computer, a computer that the user didn't know was infected with malware. Malware may intercept the data to be signed and replace them with a modified bank transfer, for example, to an account with a foreign number. Instead of fraudulent transfers to foreign number accounts, Malware will not be able to recognize that the user has already signed a bank transfer to the foreign number account and directed / authorized / accepted payment. Displays an error message.

  The prior art proposes several possible methods and systems for preventing abuse. For example, a special purpose terminal with its own terminal display can prevent malware from entering the terminal. However, this has the disadvantage that such terminals are only expensive for special purposes.

  Therefore, the present invention preferably uses a flexible and cost-effective PC as a terminal with a display, where additional safety measures can prevent unauthorized actions initiated by malware. .

  Thus, DE 199 23 807 relates to a method for improving security in digital signatures. The method is substantially based on a cryptographic combination of an external display and a chip card. For this purpose, data is transferred via an encoded communication channel between the display device and the chip card. In particular, the chip card knows the public code of the display device, and the display device knows the public code of the chip card. However, this method does not provide effective protection against malware such as Trojans. Once the malware enters the PC, it may disable the secure channel between the PC and the chip card. This is because such malware on a PC can operate almost everything and can access the encoded material stored on the PC to create a protected channel.

  The method of the present invention for increasing data security is based on using a chip card with an integrated display. The invention is such that, for example, in an unstable and unreliable environment, the data that he / she actually signs is displayed to the user, i.e. the user himself / herself signs the data he / she really sees on the chip card display (Real “WYSIWYS”) on how to ensure that. According to the invention, this is accomplished by using the display on the chip card as a reliable display to check the data to be signed. In other words, the data to be signed by the chip card is displayed directly on the chip card display. The chip card display is reliable because the chip card itself controls the display and it is impossible for malware to enter the chip card.

  Given the small size determined by the size of the chip card, the chip card display only displays a relatively small amount of information. In particular, displays often cannot display all the data to be signed at the same time. Thus, according to the present invention, the data to be signed is reduced to essential specific data, if necessary, and only these reduced essential specific data are shown on the display. The approach of this invention is that when some essential data cannot be manipulated by the enemy without being noticed--when the manipulation is recognized by a legitimate user on the chip card's reliable display--no longer an attack Based on the finding that there is no basis or motivation to start This is clearly seen in the bank transfer example. You can see the essential data about the transfer recipient as well as the amount transferred. If he couldn't change these data for his own benefit if he wasn't aware, he would no longer have the motivation to do so. It depends on the circumstances of each application in which data is displayed on the display, which data is displayed on the display, and how these data are selected from the chip card.

  An object of the present invention is to provide a method, a chip card, and a system for improving security in generating an electronic signature by a chip card. And preferably, it overcomes the above-mentioned drawbacks of the prior art.

  The problem underlying the present invention is solved by the independent claims. The dependent claims describe preferred embodiments and variations of the invention.

  In the following, digital signatures and electronic signatures are used as synonyms, but the definitions and terminology used in the German Electronic Signature Law (SigG) are emphasized. Here, the term “electronic signature” is used to define three types of signatures. Related to the method and system of the present invention are those types of signatures that are based on mathematical or cryptographic methods or algorithms, in particular “qualified signatures” that have a so-called legal effect. ")".

  Further, the term “essential data” refers to data that is particularly important in the signing process. In other words, the essential data is a partial data of the data to be signed that is particularly suitable for succinctly characterizing the data to be signed. In this context, the term “partial” data is not limited to parts, in particular, relatively little data that can be displayed on a chip card display in which the data to be signed is integrated. It should be noted that at some time, all data to be signed may be selected as partial data. In the case of bank transfer, the following items are selected as essential data, for example. Account number, bank identification code and amount. In addition, data describing the transfer process, such as subject, may be ignored when selecting essential feature data. That is, these data may be regarded as auxiliary data, not essential. In other words, such data should be viewed as critical data that is critical or important or special to the signing process.

  Next, two preferred embodiments relating to the method of the present invention will be described in detail.

  According to the first embodiment of the present invention, the chip card is simply used for a single predetermined purpose (eg banking). As a result, the particular system determines the data format displayed by the chip card, and thus also the essential data. The (reduced) essential data is in this case the account number, the bank identification code and the amount.

  According to the second embodiment, the multi-purpose chip card can be used for several purposes, for example banking transactions as an alternative to handwritten signatures. The essential characteristics of the data are therefore defined differently for different applications of the chip card. In the second embodiment of the invention, the essential data shown on the chip card display among the data to be signed is marked and selected according to the application. Marking and selection occurs automatically or may be performed by the user.

  In either case, processing or selection means, for example in hardware or software, to pass relevant or essential data from the data stream to be signed and display them on the chip card display. Provided in the form of chip cards.

  According to the second embodiment, a special order and mode of operation is observed so that signature generation occurs correctly, and according to the signature criteria, the signature generated by the chip card is already spread out of the chip card. May be verified by a signature verification component.

  The method and system of the invention has the advantage that signature settlement occurs, for example, by entering a signature PIN only after visual verification of the displayed essential data.

  The invention also relates to a chip card for carrying out an improved method for improving the security in the generation of electronic signatures or in the digital signature of data. The chip card of the present invention may be designed as a contact chip card, a contactless chip card, or a chip card accessed by both a contact interface and a contactless interface.

  In the chip card according to the present invention, a display designed to be as large as possible is integrated in or on the chip card so as to display as much information as possible. The display is provided with a display on the front side and / or the rear side. In the case of a contact chip card in which the typical gold contacts of the chip card module are arranged on the front side, a larger display may be provided on the rear side. The display may be based on, for example, organic display technology or plastic technology. All displays that are small enough to be on or in the chip card are suitable. Security improvements are realized in particular by addressing the sole interface of the display with the chip card's macro processor. Therefore, only the data processed by the chip card microprocessor is displayed. As a result, a display integrated on or in the chip is a reliable display.

  Preferably, the chip card of the present invention has a control element such as a scroll button or a scroll pad. The control element allows the user to scroll through the data or information displayed on the display.

  The invention also relates to a system for enhancing security in digital signatures of data. The inventive system preferably includes the chip card of the present invention and a compatible chip reader / writer, and preferably also includes a terminal and a terminal display. The chip reader / writer according to the present invention is preferably designed such that the display on the chip card remains visible during communication between the reader / writer and the chip card. For contact chip cards, this is accomplished by designing a portion of the reader / writer to be transparent so that the underlying display is still visible when the reader is connected to the chip card contact. According to a further embodiment, the reader / writer may have a recess that allows the user to see the chip card even when the chip card is inserted into the reader / writer.

  Due to the relatively small display on the chip card, only a limited amount of data or information can be displayed there. Thus, the essential point of view of the present invention is intelligent data selection, i.e. a small part that is sufficient to make the user visible to all important aspects of the data to be signed out of a large amount of information. Is selected. The selected data is preferably an essential part of the data to be signed. In one embodiment, the data that the user considers essential can be selected. According to another embodiment, the selection of essential data is made automatically. This is particularly advantageous when the chip card is a chip card provided for a single specific process, such as a bank transaction. Because the essential data is already predefined for this particular process, these predefined intrinsic data are automatically selected and subsequently displayed on the chip card display.

  Preferably, the selection is based on data marking. That is, the marked data is selected and displayed on the chip card display. Preferably, the marking, ie the base for selection, is performed by a predefined marker, preferably a text-based marker. A text-based structural language such as XML is particularly desirable.

  Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 shows an inventive system for performing the signature process of the present invention.

  Based on FIG. 1, the bank transfer process already described above in the prior art will now be described using the method of the present invention.

  In a bank transfer, for example, a payee, an account number, a bank specific code, an amount, and a date can be selected as essential data or considered as essential data. Therefore, the display 5 integrated on the chip does not need to display all data necessary for executing the bank transfer. Rather, it is sufficient to display essential data that sufficiently accurately characterizes the transfer process to the user. Based on this essential data, the user can confirm that the correct amount has been transferred to a legitimate person at a time when an accurate amount is desired. Thus, after visual verification of data that is essential to the user, the user can sign a bank transfer, i.e., confirm / instruct payment. If for some reason, for example, data has been manipulated by the terminal malware, the manipulated data is displayed on the display 5 in the method of the present invention. The user will recognize this and will not sign the manipulated data.

  In the exemplary transfer process of FIG. 1, a terminal 2 and a terminal display 1 are prepared. This may be done, for example, at a bank or at a station, with a personal PC serving as the terminal 2 and a computer screen serving as the terminal display 1. Further, a chip card reader / writer 4 is prepared for reading the chip card 5. The user guides the chip card 5 to the reader / writer 4. Here, in order to establish communication between the reader / writer and the chip card, it is sufficient that only the front part of the chip card 5 with typical gold contacts is introduced into the reader / writer. The rear part of the chip card has a display 5 that can be seen even when the chip card is in communication connection with the reader / writer.

  When the user starts the bank transfer process, detailed transfer process data is displayed on the terminal display. In addition, according to the method of the present invention, data is communicated to the chip card and a cryptographic hash value is computed by a cryptographic hash function that produces a digest of the input data. The hash value is a short fixed-length scalar value calculated from input data of an arbitrary length, and is sometimes called a message fingerprint. This is because the hash value clearly identifies the message in consideration of the nature of the cryptographic hash function.

  For example, after entering a personal ID number (PIN) or scanning a biometric feature, the user authenticates himself as an authorized user of the chip card, and then the electronic signature is (hash value) on the chip card. Calculated). This electronic signature is sent from the chip card reader 4 to the terminal 2.

  If all the data is to be displayed on the chip card display, the data set or complete data set is not marked and displayed on the chip card display.

  If only an essential part of the data to be signed is to be displayed, the chip card processor looks for a mark in the data set and only the essential data is selected based on the mark. . The data without the mark is directly sent to the hash function and is not displayed on the chip card display 51. When the mark portion is found in the data set, the mark (eg, <moneyorder> or <iban>) is removed, and the marked data is selected for display on the chip card display and passed to the hash function without the mark. Sent. In other words, the hash value that is ultimately signed is based on unmarked text data. In this regard, the inventive process in particular guarantees the order in which data is provided to the hash function in order to maintain and support compatibility with standard signature verification components.

  Of course, the method of the invention is applicable to other processes to be signed. For example, in a contract between two parties, it is possible to display only essential data such as the contract party name, contract name, date, and possibly key terms of the contract.

Claims (13)

a) Prepare a display integrated with the chip card,
b) Prepare a terminal (2) and a chip card reader / writer (4) for transmitting data to be signed from the chip card (5) to the terminal (2) and from the terminal to the chip card,
c) During the data communication between the terminal (2) and the chip card (5), the data communication between the chip card (5) and the terminal (2) in a state where the display (51) is substantially visible to the user. Establish
d) start the signing process;
e) sending the data to be signed and whose essential elements are characterized by a mark to the chip card,
f) selecting the essential data from the data to be signed by the selection means on the chip card,
g) Display the selected data on the chip card display (51),
h) A method for increasing security in the generation of an electronic signature by a chip card (5) comprising the step of sending a signature from the chip card (5) to the terminal (2) and signing the data to be signed. A chip card (5) comprising a display integrated in a chip card adapted to a predetermined signature process;
Providing a chip card reader / writer (4) with visible access to a chip card display (51) integrated in a chip card reader / writer adapted for a predetermined signature process;
Establish data transmission between chip card reader / writer (4) and chip card (5),
Initiate a predetermined signing process,
Transmit the data to be signed from the chip card reader / writer (4) to the chip card (5),
Mark the essential data from the data to be signed,
Based on the mark, the essential data is selected by the selection means of the chip card itself,
Display these selected data on the display (51) of the chip card (5),
A method for increasing security in the generation of an electronic signature by a chip card comprising the steps of signing data to be signed and transmitting the signature from the chip card (5) to the terminal (2).   The method of claim 1, wherein a hash value to be signed is formed based on the data to be signed.   4. The method of claim 3, wherein the hash value is based on unsigned data to be signed.   The method of claim 4, wherein the marks are removed to form a hash value.   A method according to any of the preceding claims, wherein the marking and / or selection step is performed automatically for a predetermined signature process.   A method according to any of the preceding claims, wherein the marking and / or selection step is performed manually for the signature process to be performed.   8. A method according to any one of the preceding claims, wherein the step of scanning the data transferred for a marker is performed between the start step and the selection step, the selection being based on a mark. .   The method of claim 8, wherein the mark is based on a text-based structural language such as XML. A chip card (5) having an integrated display (51) for increasing security in the generation of electronic signatures,
A chip card comprising selection means for selecting essential data from data to be signed and displaying the selected data on an integrated display (51).   9. The chip card according to claim 8, wherein the selecting means selects essential data based on the mark.   Chip according to claim 8 or 9, characterized in that the chip card further comprises a control element (6), the scroll of the display (51) on the chip card (5) being controllable by the control element. card. Chip card (5) according to any one of claims 8 to 10,
A chip card reader / writer (4), wherein the display (51) of the chip card (5) is at least partially visible during data communication between the chip card reader / writer (4) and the chip card (5). A system for improving security in generating an electronic signature, characterized by comprising a chip card reader / writer designed in the above.

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